⚡Shock⚡ through the heart,

[Hedges]

And you're to blame,
You give solar a bad name!

Meant to be safer than a cheater cord, power cord with shrouded banana plugs

+

Similar wire and banana connected to equipment under test. Now it's easy to stack banana plugs and plug in HV scope probe.



It's just as easy to mix up Line and Ground connections, resulting in hot chassis.
Use UPS to create 208 or 230V at 50 or 60 Hz for testing, then put one hand on DUT chassis, and touch test equipment with other hand.



before:


after:

(file photos)

Good thing I just completed my QEW (Qualified Electrical Worker) training (again) the day before.
So I knew that when current passes through the chest, you should get a medical checkup.
And that AC in particular is good at scrambling ion polarities in cells of heart muscle.

Lesson learned, best practices:

1) Use keyed connectors on cable providing power and ground to DUT.
With Y-cable, branch off to banana cables to test equipment.
This way, chassis is not accidentally electrified.

2) Use a separate ground cable, perhaps with large alligator clip, as redundant ground.

3) Consider GFCI (RCD) to power DUT. In this case, wall outlet likely not effective due to UPS, so use portable GFCI suitable for voltage range.

 

[rodrick]

Note to self diy defibrillation not good, thanks for the reminder we all get complacent but we have to remember this is serious ?

 

[Rednecktek]

Tag line is there for a reason. 120v tickles, 220v stings, 440v hurts like hell but when I got bit by 600v I invented new obscenities!

 

[efficientPV]

What are you complaining about. I no longer have a heart rate!

 

[Hedges]

I think that resembles:

https://ecglibrary.com/vf.html

My recommendation (note I am not a licensed cardiologist) would be to perform the procedure described in original posting, then take another EKG.

Repeat until it resembles:

https://ecglibrary.com/norm.php

If you do not have immediate access to EKG machine, simply checking for a pulse may be sufficient.
In the mean time, mechanical ventilation and chest compressions are recommended.
A pulse oximeter would be useful to gauge effectiveness. Sufficient oxygenation is required for the shock to be effective.
Don't give up! Like me, you might be able to return to the world of the living.


I had suggested to my colleagues they take CPR/AED classes. Those are offered, but weren't being advertised for employees. I've recommended they be required for all Qualified Electrical Workers, ideally all employees who work in areas where shock might occur. And offered to all employees.
I had the opportunity to learn AED use in a couple prior jobs (now, even untrained individual are authorized. "press 1 for English, press 2 for Spanish" and the AED will walk you through the steps.) CPR and various other first aid and rescue dating back to my teenage years, although I never actually went on to any jobs or volunteer work which required it. The training has been useful on occasion when encountering an accident, and for DIY care. I recommend the training for all.

Check first with your employer. Might be offered on-site and on the clock. Otherwise, available in the community.

Red Cross Training | Take a Class | Red Cross

Sign up for one of our top Red Cross programs. Classes include First Aid, AED, BLS, CPR, EMR, swimming, water safety, babysitting, child care, and more!

www.redcross.org

Lifeguard Training & Certification | Red Cross

Stay safe around water. With lifeguarding and water safety programs from the Red Cross, you can learn basic skills and train to be a lifeguard.

www.redcross.org

 

[Hedges]

I have not been able to investigate the setup yet (off limits during accident investigation), but I want to find out how the UPS output is bonded, or floating, etc. I suspect it is galvanically isolated but has large filter capacitors, or something else that I believe split the 230V output to about 30V/200V, based on scope display which I think reflected voltage between neutral and ground.

Measuring my own hand to hand resistance with DMM, I got 300k ohm. With LCR meter at 60 Hz, I got 150k ohm. At 230V, those would have delivered 0.7 mA or 1.5 mA, a harmless tingle.
Reading up on the topic, body resistance is 500 to 1000 ohms, but skin is much higher. At elevated voltage, skin breaks down. Now I'm looking at currents like 0.25A to 0.5A, damaging and lethal in a short time.

Something of a contradiction in my reaction. There was no involuntary tightening of muscles but there was fibrillation or at least dysrhythmia of heart muscle. Threshold is between 30 mA and 500 mA, depending on duration (I think 50 to 300 milliseconds.)

Log-log graph of the effect of alternating current I of duration T passing from left hand to feet as defined in IEC 60479–1.[24]
AC-1: imperceptible
AC-2: perceptible but no muscle reaction
AC-3: muscle contraction with reversible effects
AC-4: possible irreversible effects
AC-4.1: up to 5% probability of ventricular fibrillation
AC-4.2: 5–50% probability of fibrillation
AC-4.3: over 50% probability of fibrillation

Electrical injury - Wikipedia

en.wikipedia.org

 

[efficientPV]

Not dead yet. Though a few doctors have tried to kill me. It is all rather casual. After being at my camp a few weeks last June my cardiologist called me.

You need to come into the office. We need to schedule surgery.
You know I'm a thousand miles away.
When are you getting back? Two weeks?
No, October.
OK, we can do it then.

That didn't get scheduled till January. They are getting another try Wednesday. Don't they say fifth times a charm.

 

[HowlerMonkey]

When I was a kid, someone had cut an extension cord with a hedge trimmer.
Free extension cord so we stripped the ends and decided to see who could hold on the longest.
All was fun until both wires touched together.

 

[Quattrohead]

Oh shit, that hurt.
I just saw that my one panel banks was not producing and went out to investigate and found one of my Y connectors all burned up. Thinking I will be fine grabbing the wire or the mc4 connector but I got a really nasty around 200 volt DC shock. Then I noticed a salty Crystal like deposit around the connectors and realized that it is rather conductive. To be fair to that Y and the mc4s they were lying on the ground and we did have massive amounts of rain in the past couple days. Lesson learned don't dangle you was on the ground even with a temporary lash up.

 

[Hedges]

Sounds like poor seal allowed moisture to form connection from inside to outside.

Which came first, water intrusion on burned connector?
We've learned that "MC4" from various vendors are not compatible. I would guess any "Y" is suspect, likely cheap connectors.
We're supposed to only use same brand/model together, or pairs that received UL listing together.

 

[Hedges]

Whoops, he did it again!

High Frequency Inverter battery current waveform

In the interest of science ;) I have captured waveforms drawn by a high frequency inverter from the battery. This could give some insight to how a BMS might react. About 25 years ago I found myself with idle hands and some money ($800?) burning a hole in my pocket. I wandered into Quement...

diysolarforum.com

StatPower HF MSW inverter created 60 Vrms on chassis relative to negative battery cable and truck chassis.
After turning off power, it continued to make AC for a while and shocked me (not that I expected hot chassis even on).
I need to confirm it is OK to bond battery negative to inverter chassis. Anodized aluminum and painted metal may have insulated inverter from truck.

 

[Mattb4]

I got shocked yesterday when hooking up my PV shunt because I thought it was good enough to turn off the breakers to the PV array (sun not up) but not completely de-energize my AIO. When I attempted to attached the mounting screw to the shunt from the negative PV wire from the AIO I got a decent shock. Not what I was expecting at all. I then turned off and opened all breakers to the AIO. Checked for voltage on the PV negative before connecting (no shock) up the shunt.

Been a long time since I last got shocked.

BTW, it is hard to own up to being a complete idjit when I get caught like that.

 

[Hedges]

"PV shunt"?

We've heard of AIO putting AC on PV connections.
Shunts, normally is on battery. What is your PV shunt for?

If AIO architecture has PV go through buck to battery, I wouldn't expect common-mode AC on PV.
If PV goes to HV DC before H-bridge to make AC, then I would not be surprised if it carried rectified negative half of AC.

 

[Mattb4]

My PV shunt monitors my PV array. You can see it over at my review of my PowMr AIO in the AIO sub forum. https://diysolarforum.com/threads/power-up-review-powmr-srne-pow-lvm3k-24v-h.65567/page-2

Yeah I expect with this being a high PV voltage SCC it has the 1/2 A/C voltage issue. Enough to let me know it was there.

 

[Mattb4]

Just out of curiosity I decide to do a test to see what voltage I could get by replicating the situation but testing for AC voltage with DMM instead of my hands. It was 18.35vAC. Rather strange amount.

 

[AntronX]

Shock through the heart,​

And you're to blame,

You give love to Batman.

 

[SamDeleted]

And you're to blame,
You give solar a bad name!

Meant to be safer than a cheater cord, power cord with shrouded banana plugs

View attachment 142879 + View attachment 142880

Similar wire and banana connected to equipment under test. Now it's easy to stack banana plugs and plug in HV scope probe.

View attachment 142884

It's just as easy to mix up Line and Ground connections, resulting in hot chassis.
Use UPS to create 208 or 230V at 50 or 60 Hz for testing, then put one hand on DUT chassis, and touch test equipment with other hand.

View attachment 142866

before:
View attachment 142867

after:
View attachment 142868
(file photos)

Good thing I just completed my QEW (Qualified Electrical Worker) training (again) the day before.
So I knew that when current passes through the chest, you should get a medical checkup.
And that AC in particular is good at scrambling ion polarities in cells of heart muscle.

Lesson learned, best practices:

1) Use keyed connectors on cable providing power and ground to DUT.
With Y-cable, branch off to banana cables to test equipment.
This way, chassis is not accidentally electrified.

2) Use a separate ground cable, perhaps with large alligator clip, as redundant ground.

3) Consider GFCI (RCD) to power DUT. In this case, wall outlet likely not effective due to UPS, so use portable GFCI suitable for voltage range.

Just how much of this was supposed to be read to the tune of the song ?

 

[electrostasis]

I think that resembles:

https://ecglibrary.com/vf.html

My recommendation (note I am not a licensed cardiologist) would be to perform the procedure described in original posting, then take another EKG.

Repeat until it resembles:

https://ecglibrary.com/norm.php

If you do not have immediate access to EKG machine, simply checking for a pulse may be sufficient.
In the mean time, mechanical ventilation and chest compressions are recommended.
A pulse oximeter would be useful to gauge effectiveness. Sufficient oxygenation is required for the shock to be effective.
Don't give up! Like me, you might be able to return to the world of the living.


I had suggested to my colleagues they take CPR/AED classes. Those are offered, but weren't being advertised for employees. I've recommended they be required for all Qualified Electrical Workers, ideally all employees who work in areas where shock might occur. And offered to all employees.
I had the opportunity to learn AED use in a couple prior jobs (now, even untrained individual are authorized. "press 1 for English, press 2 for Spanish" and the AED will walk you through the steps.) CPR and various other first aid and rescue dating back to my teenage years, although I never actually went on to any jobs or volunteer work which required it. The training has been useful on occasion when encountering an accident, and for DIY care. I recommend the training for all.

Check first with your employer. Might be offered on-site and on the clock. Otherwise, available in the community.

Red Cross Training | Take a Class | Red Cross

Sign up for one of our top Red Cross programs. Classes include First Aid, AED, BLS, CPR, EMR, swimming, water safety, babysitting, child care, and more!

www.redcross.org

Lifeguard Training & Certification | Red Cross

Stay safe around water. With lifeguarding and water safety programs from the Red Cross, you can learn basic skills and train to be a lifeguard.

www.redcross.org

Thank you for this link to ecglibrary as an electrochemical engineer will review accessible equipment for DIY ecg/ekg ... in past have purchased AED devices for sites that I've worked at, but never actually looked into the ecg/ekg equipment itself.

 

[electrostasis]

Also, keep in mind that it is not just electricity, but also EMF that can mess with your central nervous system CNS and heart. This is specifically important for wireless use cases and directed energy systems such as point to point microwave antennas.

 

[AntronX]

This is specifically important for wireless use cases and directed energy systems such as point to point microwave antennas.

No, LOL. Main concern would be tissue heating but not at tiny power levels used for PtP microwave links. Microwave radar maybe but only for heating.